LOCATION: Ottumwa, Iowa

PROBLEM: The Ottumwa Generating Station needed to replace its coal ash conveyor inside of the plant. The issue was that the 138-ton conveyor needed to be lifted 10 feet off the ground floor to be secured in place. The interior of the powerplant has low headroom and congested space, which precluded the use of a crane or bulky cribbing stacks.


SOLUTION: Our engineers and design-build experts studied the situation and determined that a custom modular lift system would be required for this complex project. They developed three lifting plans: one to move the conveyor adjacent to the boiler; one to set four hoppers onto the conveyor; and a final plan to elevate the assembly 10 feet to allow installation of new permanent legs. The team used 3-D modeling to develop the lifting plans to avoid surprises when the equipment reached the plant.

Engineered Rigging designed a lift system featuring 16 omnidirectional load skates each with a 10 ton capacity, and 12 custom-fabricated 23-foot-long support beams each with a 19-ton capacity. A single remote operator was able to safely control the system’s 24 lifting columns. As the columns raised the conveyor, they mechanically locked into place to enable work to be done without a suspended load — a key safety feature. The team also designed a lift fixture for placing the hopper sections on top of the newly secured conveyor.

The modular lift system was rapidly assembled inside of the plant in just two days of double shifts. Once the lift system was installed, it lifted the 138-ton conveyer into place and positioned it on grade with a total lift time of only 30 minutes. Tear-down was accomplished in a single day of double shifts.

“Having an in-house engineering team, fabrication facility, technical support team and fleet of heavy lift equipment at our disposal, Engineered Rigging is uniquely equipped to quickly identify and implement effective, affordable solutions for complex projects like the installation of the Ottumwa plant conveyor. From design to fabrication and implementation, the entire project was completed in just 16 weeks,” said Engineered Rigging’s President, Christopher Cox, P.E.

Engineered Rigging can customize our modular lift system’s gauge and column spacing to lift loads of various lengths and widths. This versatile system is suitable for a variety of applications. It is currently available for projects in North and South America. For more information, please call 844.474.4448.